Accurate zero current detector circuit in switching regulators

Abstract

A switching regulator circuit includes a gate driver circuit driving a first switch and a second switch to generate a first voltage at a first node. Further, the switching regulator includes an LC filter circuit responsive to the first voltage to generate a desired output voltage. Moreover, the switching regulator includes a regulator circuit coupled to the LC filter circuit to control the gate driver circuit. The regulator circuit accurately controls variations in trip point. The trip point is a voltage at which the second switch is switched OFF by the gate control circuit. The regulator circuit includes one of a Delay Locked Loop (DLL) and a Pulse width modulator (PWM) controller.

What is claimed is: 
     
         1 . A regulator circuit for controlling variations at a trip point of a switching regulator circuit, the regulator circuit comprising:
 a sample and hold circuit to sample a feedback voltage at a first instance to generate a first voltage signal; and   a pulse width modulation (PWM) controller to control conduction time of a switch, the PWM controller comprising;
 an error amplifier operable to receive the first voltage signal and a first reference signal to generate an error signal; 
 a ramp circuit to generate a ramp signal; and 
 a comparator operable to receive the error signal and the ramp signal to generate a control voltage signal, wherein the control voltage signal controls variations in a trip point of the switching regulator circuit, wherein the trip point is an instance when an inductor current flowing through an LC filter circuit is equal to zero. 
   
     
     
         2 . The regulator circuit as claimed in  claim 1 , further comprising a gate control circuit to control switching ON and switching OFF of the switch. 
     
     
         3 . The regulator circuit as claimed in  claim 1 , wherein the feedback voltage is a voltage across the switch in the switching regulator circuit. 
     
     
         4 . The regulator circuit as claimed in  claim 1 , wherein the LC filter circuit filters the feedback voltage.